Automatic measured service telephone system



Dec. 4, 1951 c. E. LOMAX AUTOMATIC MEASURED SERVICE TELEPHONE SYSTEM Filed Oct. 4, 1947 oziobiz 7? m m N I R 0 c 0 L 3:5 25; 85 m E. 6. 8 w m I e m $35G o I? m. c H 5,55 o w 1 m ll? v. M m. B 8 No. il Em mn n @z I8 w I 228 0:2 I- o 20E ||l mOSmEGE 5&3 9 $38 2 8 525 .8

. E 80 A .8 N8 E EQ 55 8 c E 8 5o 0 2 .Q.l 0 A O v $28228 .2 0 25 8 8 c -Q I, z; 8 mm is m Patented Dec. 4, 1951 rnnnenonn SSTEMf I Qlarence'E. Lolnax,LChicagoIll assignor.tp AW :tomaticElectric Laboratories,-,.- Inc., qhicago m .alcorporationof Delaware ApplicationDctoberA, 1947; Se1fizilNo. 77?;934

The, present invention relates to.r;-automatlc telephone :systems;=and"imre marticularlyttors'uch systems embodying:measure,dzservicegfacilities., :aInaconventional'.telephonetsystem-nf;the:type noted comprising ."party jsubscriber lines, :thejcirdreams (01. i'ze-" asi fora-selectively operating jthe meter individual to cuittarrangementsithat;are -;employ,ed .to' insure individual ,zmetering of the;ser,vices rendered. to each ;,p-a1:ty subscriber substation oniieachjjparty subscriber line :are considerably complicated, rendering rather expensive :,the ..cooperating :618.-

mentsaofithetsystem. a I

' .incc'ording'ly, it. zisea general object of the L-presentrinventionato provide-- :in. an automatic measured service :telephone system including party subscriber .lines, :an; improved: and: simplified: circult arrangementiorrmetering the .servicetrenderedato each partysubscriberggsubstatione on each partyzsubscr-iber line. 1 A

iAnother 'objectxof the :invention is "5170 provide ina te1ephone-.system-;of:the type-notedan im proved -meteringyarrangement, whereby {the first meteriindividual ito the; first;party isnbscriberisubstation: on gthe'gparty subscriber line reads directly the service rendered to the first party: uh: scriber n su'bstation :while the :second :meter :individual i to ethQqSGCQl'ld. ':-party 1 Subscriber substation on ithe partyssnbscriber. ,line reads the :combined servicesvrendered both -to the first gparty isubscriberq snbstation and to the second party :1 subscriber substation. I wranother abject of'ithe invention .,:is tozprovide in; --rtelephone-. system ofi-thetype noted, ga n im--v proved dine circuit -associated @with aeach itwoparty zsubscr-iber linethat includesitwo metersdna dividual to the respective two partyzsubscriber substations, 1wherein=the magnet of '1one--.-of@:1the' meters isaof :the imarginalatype {permitting selec-' tive operation'ofthe magnets mentioned-maria singleecondnetor employing high .-and .;lo.w :volta g es I .v ll fnnther-pbjectofthe inventiomis to;provide i nautomatic=.-measured service telephone sysemflen imp edi ei n conductor a ange-- ment for selectively operating-{the metersassociflie .i s b e i r vs i es -b sh 011 6531 3 2. r tA fuiitherrobject of rtherinventionsis to provide an.an t'omatic measured.service telephone sys .t In, improvemswitching. links for extending the connections and for ,selectively .operating the meters associated with {the subscriber lines chidedfiniconnections extended .thereby. --A,.fnrther. object. of the .inventionis 110 provide in nag. switching l link of the .character .notefd, an improved arrangement includmg a high voltage boostefbattery arid ajlow voltagelboo's'ter battery merits-of thesystem, whereby=the above-outlined thexcalling subscriberrsubstation connected to the subscriber line :that is connected thereto.

."n-sstillsfunther. object; of the-invention is to provide inua switching-link of the character noted, an improved timer' arrangement for :selectively operating the ;.meter individualto theksubscriber line .thataisiconnectedathereto.

Further :features ,of :the invention pertain .to the particularxarrangement of the circuitreleand additional nperating features thereoiqareattained. I

flhe.;invention,'-.both as to itslorganization and method "of :operation, together :with, turther tob- I jects and; advantages; thereof, will best be under 7 stood :aby reference-"to the i-following. specification taken in connection with the accompanying drawing :in which the single figure: illustrates-the details of :an automatic telephone system having incorporated :therein ,thezqfeatures 0f -the;prese nt invention.

Referringwnow zmore particularly-to the drawing, tthere vvis illustrated zan automatic telephone systemeomprisingracentralsexchange 1| 00 and a plurality of distant exchanges, including thedistantexchangedfll. The central exchange-.lflfl-iis connected to each; of the -.distant exchanges .by a group {of-drunk lines extending. therebetween, vthe central? exchange-J00 being connected to theidistantexchange gl ill .'b,y;agroup of trunk ,linesjin eluding ttheytrunk line ;f.; The telephone sys tem is divided into 2 zones withrreference .to the central exchange I00 whereby the distant .exchange :I-ill :mayreside .in the second zone with respect to the, centralexchangel 0.0 vandother of the distant exchanges. not shown,. may ,-1 'eside;,in first and ,third zones with respect to -the, central exchange l 80. {ll-he central: exchange .I 00 Land eachofthe distant exchanges I0.l,-etc.,-:-are otithe automatic ;type, each serving .a group .of subscriber-substations. and. being provided with automatic switching apparatus".

' More particularly, the central exchange serves; :party subscriber substations including the party subscriber substations A and. B andprivate subscribersubstations including rthe 'private subsoriberjsubstationec. The,.party subscriber. substations..A.and.-B. are arranged on "a party sub: scriber .line ..!I .,.provided with .a line. circuit ll'l lindividual .thereto; -.while the ,private subscriber substation C .is. arranged .on a,,.private subscriber line-v lfllprovi'ded .-withlalline .circnit l9,3. individual thereto. 'As .previously noted, the .central sexchange lfilfi comprises automatic switching ape paratus. mnuaingapmrant ofmgroupsof finder- 3 selector links and a corresponding plurality of groups of connectors. One of the groups of links includes the link 25 illustrated consisting of the finder 26 and the selector 21. Further, each group of links is provided with a distributor, the distributor I I being individuallyassociated with the group of links, including the link 25. The finders 26, etc., of the group of links, including the-link 25, have access to the group of subscriber lines including the party subscriber line I; while the group of connectors, including the connector 192, has access to the group of subscriber lines, including the private subscriber line I94. Also the selectors 21, etc., of the group of links, including the link 25, have access to the different groups of connectors and to the different groups of trunk lines. Specifically, the selector 2'! has access to the connector I92 via a trunk I9I extending thereto and to a trunk 80 terminated by a trunk circuit 90 that, in turn, terminates one end of the trunk line 95'. The other end of the trunk line 95 is terminated in the automatic switching apparatus I previously mentioned disposed in the distant exchange I-0l.

'As previously noted, the distant exchange I0| serves a plurality of private subscriber substations, including the private subscriber substation D, and a plurality of party subscriber substations, not shown. The private subscriber substation D is arranged on the private subscriber line I02, is provided with a line circuit, not shown, and is accessible to and has access to the automatic switching apparatus I05. The apparatus arranged in the distant exchange IOI may be entirely conventional, the automatic switching apparatus I05 preferably being of the Strowger typ . In the central exchange I00 each of the private subscriber substations C, etc., and each of the party subscriber substations A, B, etc., is provided with conventional subscriber substation apparatus. Also each first-party subscriber substation A, etc., on each party subscriber line I, etc., is rovided with a dial having a set of oil-normal springs that is operated each time the associated dial is operated to transmit a. digit in order to ground the positive line conductors of the associated party subscriber line for a purpose more fully explained hereinafter. Preferably, the line circuit individually associated with each 'party subscriber line is identical to the line circuit. I! individually associated with the party subscriber line I; which line circuit I 1 comprises a line relay R20, acut-off relay RIO and two meters MA and MB respectively individual to the two party subscriber substations A and B connected to the party subscriber line I. Also the line circuit I1 is'operatively associated with the distributor I I0. The finder 26 of the link 25 may be of the conventional Strowger type; while'the selector 2'! of the link 25 embodies av conventional Strowger mechanism 10, a timing switch 90, and a relay group, shown in skeleton outline and including a linerelay RI I0, a party relay RI29, a switching relay -RI30, a meter relay R140, a transfer. relay R159, a pick-up relay RISE, an answer relay EHO, a hold relay RIM), a test relay RI 05 and a magnet transfer relay, not shown. The Strowger mechanism I0 is of conventional construction and arrangement including a vertical wiper 14 provided with an associated vertical contact bank and three ordinary wipers I I, 12 and 13 provided with an ordinary, contact bank, a vertical magnet, notshown, for driving the wiper carriage step by step in the vertical direction away from its nor- 4 mal vertical position, a rotary magnet, not shown, for driving the wiper carriage step by step in the rotary direction away from its normal rotary position, and a release magnet, not shown, for releasing the wiper carriage and for causing it to be returned to its normal rotary-and vertical positions. Also one or more sets of switch springs, not shown, are associated with the wiper carriage of the Strowger mechanism 10 and are operated when the wiper carriage is driven one step in the vertical direction away from its normal and 95 provided with associated contact banks and a rotary magnet M9I for driving the wipers .noted step by step in the clockwise direction.

Also the link 25 comprises an ordinary 48 volts exchange battery indicated at EH48, a 40 volts booster battery indicated at BA40, and a 20 volts boosterbattery indicated at B320.

'Also in the central exchange I00 an impulser is commonly associated with the links 25, etc., and comprises a motor M6I of the constant speed variety adapted to be operated from a commercial source of A. C. power indicated, matching relay RISE! and an operating shaft carrying five cams C6l, C62, CZBI, CZ62 and CZ63. The cams C6I and C62 are employed for common control purposes; whereas the cams CZGI, CZ62 and C263 are employed for zone metering purposes and respectively constitutes the zone metering cams for the first, second and third zonesof the telephone system. Specifically, the three zone cams CZBI, C262 and CZ63 are provided with respectively associated zone switches SZ6I, S262 and S263 respectively terminating the zone conductors C6I, C62 and C63; which zone conductors C6l, C62 and C63 are respectively terminated in the third, second and first contacts in the vertical contact bank associated with the vertical wiper M of the Strowger mechanism I0 and are utilized for a purpose more fully explained hereinafter.

The trunk circuits etc., may be of any suitable type; the connectors I92, etc., are preferably of the Strowger type; and the line circuit I93, etc., individually associated with the private subscriber lines I94, etc., are of any suitable type including a meter.

A better understanding of'the connection and arrangement of the apparatus incorporated in the telephone system will be facilitated from a consideration of the extension of various calls from the central exchange I00.

Considering now the extension of a local call in the central exchange I00 from a calling second party subscriber substation, such for example, as the second party subscriber substation B to 2. called private subscriber substation, such for example, as the private subscriber substation C, the subscriber at the calling second party subscriber substation B first initiates a call, thereby to complete a loop circuit, including the coni tacts II and I2 and the line conductors C2 and C3 of the subscriber line I, for energizing the winding of the line relay R20 in the line circuit I'l individually associated with the party subscriber line I. When the winding of the line relay R20 is thus energized it operates tocomplete, at the contacts 2I, a path for applying battery potential by way of the winding of the cut-01f relay RI 0 to the control conductor C4 of the party subscriber line I; and to complete, at the contacts 22, a path, including the contacts I5, for applying ground potential to the eg smces 5 start conductor (36: extending to: the-distributor I401 Assuming. that the distributor" 1 Mi has: selected? the link 25 illustratedivia theiconducton G- at. this time; operationof: the finder 2.6 of the link. 25 is: initiated;;: whereby thefinder; 2.6; operates; to. find the calling: party: subscriber: line;

I: whereupon ground potential in the'finder 26- is: applied to the control' wiper 81 thereof. and; consequently to the control conductor 04-. of the. calling subscriber: line If completing a; circuit. substantially identical to that previously traced forsoperating'the cut-ofiirelay-Bm. Upon operating the cutroff relay. RIO completes, at. the.- contacts-. a point. in multiple: to the contacts. 2.:I intav holding circuit for. energizing; the winding; thereof; prepares, at the. contacts: I3, acircuit traced: hereinafter for operatingv the magnetMB offtheassociated meter; and completes, at the contacts I 61, vaepath. for applying ground. potential to-the control conductor 05. of the party, sub;- scriber line I in order to mark the party-subscriber line I as busy to the connectors having, access: thereto. Also the cut-01f relay R10 interrupts, at the contacts I5, thepath-for. applying; ground potential tov the start conductori C6 extending to the-distributor H0; and interrupts, at. the'contacts. II and I2, the loop circuit. for, energizing the winding of the line relay R20; whereby the-latter relay, being of theslow-torelease-type; restores shortly thereafter. Also atand the contacts 13!, I33, for energizing/in series theupper and lower windings of the party relay R120 and the line relay EHO; in the selector 21. When; this loop circuit is completed,v the line relay RI-I0- operates; however, the partyrelay R.'I20-.- does notoperate as it isof the differential. type.- Upon operating the linerelay RI I0 completes, at the contacts III, a circuit, including the contacts 31-, for operating. the holdrelay R100. Upon operating the hold relay RI00 preparesatthe contacts I03, a dialing path. to the. dial conductor CI00; prepares,.at the contacts IN, a circuit traced hereinafter forv the test relay RI; and completes, at the contactsv I02, apathfor applying ground potential to the controlwiper 8 of the finder 26f in order to retain.

operated the cut-off'rel'ay R10 in the line circuit Hand the finder. 26... Also at this timethemag netitransfer relay,.notv shown, is operated and the. left-hand windingof the answer relay R110 is energizedover a circuit, not shown, in order to pole. the latter relay for subsequentlopera tion.as explained more fully hereinafter.

A't-thistime th ubscriber at'the calling'party' subscriber substation B dials the three digits comprising the directory number of the called private, subscriber substation C. The line relay RI'Iflfollows the impulses of the first digit repeating, at the contacts. I I2, the impulses thereofthe hold relay R'I00; whereby the latter relay is retainedin its operated position during impulsing as it is 'of'the slow-to-release type. At the conclusion of the first digit, the line relay R1 Ill is retained in its operated position, and

shortly thereafter the magnet transfer relay, not shown. restores: .in-.:-order to, enact intermittent: operatiorr-v of the rotary magnet; not shown, of: the. Strowger' mechanism I0. More particularly; atr-thisatime-thestrowger mechanism I0 has respnmledftostheffinstidigit of the, directory number: and has: selected the group of. trunks; including; the trunk I9I and operation thereof is initiated tu:search fors-anidletrunk in the selected group. Assuming: that." the trunk I9I extending to the:

connector-I92 is'the first'idletrunkin the." group.

mentioned? when; it is. selected by the. wiper set: of" the Strowger. mechanism battery potential the. control :conductor thereof is applied to the: control wiper" I3 of the; 'Strowger mechanism; 10 completing a. circuit, including the contacts IOI, forroperatingthe testarelay RI0'5. Upon opera't'-.- mg the test. relay RI05- interrupts, at the C011.- tacts IMF, the previously traced. circuit for; en:- emizingx-the winding of? the hold'. relay RAM in order t'oscausethelatter'relay to restore. shortly thereafter; it. being of the slow -to-release type. Al'soithe'rtest're1ay'R'I05 completes, at: the con-- tacts. Iii6.,.a circuit. for operating the switching relay- BI30;'. and? also arrests operation of the rotary magnet, not shown, of the Strowger mechanism 5710:. Upon operating the switching: relay: R130 completes, at: the contacts I35 and E35, a holding circuit, alsoihcluding the contacts I 32, for energizing the winding thereof :and' a multiple. path for. applying groundpotentialittof the control wiper I3 'of' theiStrowger. mechanism 70; Furtherthe switching-relay RI 30 interrupts; at the contacts. I3! and I33; the: loop circuit. ex;--= tending between the calling party subscriber sub-- station B and the party=relay RI20' andthe line: relay EHO; and? completes, at theicontacts' I32 and I34; an extensionof the loop; circuit" via-the right-hand winding of the answer relay: R110 :to;

. the line wipers "II and I2 of the Strowgermechawnism I0 and thence viathe line conductor-of-the trunk IQI to-theline relay inthe connector I:92;.. At this time the connector; IQZis' conditioned'to:

.be responsive to the second and-third.digitsdialed' at the calling: party subscriber substationiB; and operates to return groundipotential over the-con trol conductor thereof and consequently tov the control wiper I3 of the.-Strowger mechanism I0; This application of ground potential to thecontrol wiper I3 of the 'Strowger meohanismifl com-r pletes a multiple holding circuit, including thecontacts I 35 for energizing the-winding of the: switching relay-M30; and completes amultiple path; including the contacts I 42 and-I36 for applying ground potential to thecontrol wiper t:

ofthe-finder 26in order; to retain operatedthe: cut-off relay Rlil: in the line circuit- I! and the. finder 26. At this timethe line relay R110 re.--- stores interrupting; at the contacts I I I,;a.furthe'r. point in the circuit "for retaining operated the hold relay'Rl00; When the-hold relay=RIO0Z re.- stores, itrinterrupts, at the contacts I01, thecircuit' for retaining'operated the test relay R in order to cause the latter 'relay to :restore'; inter-- rupts, at the contacts I02, the original holding:

' to the-connector I 92; whereby ohly-the-switching relay RI 39 in the selector 21 is retained in its operated position. The answer relay RI'IIl is not operated notwithstanding the completed loop circuit via the right-handwinding thereof as it is not poled to operate; however, a circuit, not shown, is completed for energizing the left-hand winding of the answer relay RI'III, as previously noted.

The second and third digits of the directory numberf: dialed at the calling party subscriber substation B are transmitted over the loop circuit extending therefrom via the party subscriber line I, the finder 26, the selector 21, the trunk I9I to the connector I92; whereby the connector I92 responds to the two digits mentioned in order to selectthe subscriber line I95 extending to the calledfprivate subscriber substation C. Further operation of the connector I92 depends upon the idle or'busy condition of the called private subscriberf substation C at this time as determined by markings in the associated line circuit I93; all in accordance with conventional practice. Assuming that the called private subscriber substation C is idle at this time, the connector I92 operates to project ringing current over the private subscriber line I94 extending thereto and to return ring-back tone current over the previously traced loop circuit extending back to the calling-party subscriber substation B.

When the subscriber at the called private sub g wipers 93 and 95 of the timing switch 90 one step in the clockwise direction away from their home positions. As the motor M6I of the impulser 69 continues to operate, the circuit for opscriber substation C answers the call, the connector. I92 operates to arrest the projection of ringing current thereto, as well as the return of ring-back tone current over the loop circuit extending to the calling party subscriber sub station B. Also the connector I92 completes an operative connection between the loop circuit extending thereto from the calling party sub scriber substation B and the loop circuit extend ing therefrom to the called private subscriber substation C; and reverses the polarity of the ioopcircuit extending back to the calling party subscriber substation B; whereby the right-hand winding of the answer relay RI'IIl in the selector 2! ispoled to operate. Upon operating the answer relay RI'H! completes, at the contacts I1 I, a multiple point in the circuit for operating the motor M6I of the impulser 60; whereby operationof the motor M6I is initiated at this time unless, of course, it is already operating. The operating motor MEI of the impulser 50 rotates the cams CGI, etc, previously noted and when the cam C61 next closes the set of switch springs SSI, a, circuit,including the contacts I12 and IE3, is completed for energizing the lower winding of the pick-up relay RIGU in the selector 21. When the lower winding of the pick-up relay RIBU is thus energized, the latter relay operates to complete, at the contacts I62, a holding circuit, including the grounded control wiper 13 of the Strowger mechanism 10, for energizing the upper winder thereof. Also the pick-up relay RIGIJ prepares, at the contacts IBI, a circuit traced hereinafter for operating the meter relay RI49; and prepares, at the contacts I64, a circuit traced hereinafter for operating the rotary magnet M9I of the timing switch 90. Subsequently when the cam CB2 closes the set of switch springs SS2, the previously mentioned circuit, including the contacts I64 and I31, is completed for operating the rotary magnet M9I of the timing switch 90. Later when the cam C62 opens the set of switch springs $62, the circuit for operating the rotary magnet M9I is interrupted; whereupon the rotary magnet M9I restores in order to drive the iii) crating the rotary magnet M9I of the timing switch 9|] is completed and then interrupted intermittently; whereby the wipers noted of the timing switch are driven step by step in the clockwise direction. Preferably, the motor MEI of the impulser 60 is of the constant speed variety as previously noted and rotates the shaft upon which the cams CBI, etc., are mounted precisely one revolution in ten seconds. Accordingly, the rotary magnet M91 of the timing switch 90 is operated and restored each ten seconds; whereby the wipers noted of the timing switch 90 operate through one complete revolution in 100 seconds since each of the wipers noted is provided with ten contacts in the associated contact banks. Accordingly, it will .be understood that when the call is answered, the answer relay RIIEI in the selector 2'! initiates operation of the impulser 60; which impulser 69 may occupy any rotary position; whereby within ten seconds operation of the timing switch 90 is initiated. After operation of the timing switch 90 is initiated it completes a timing operation every 100 seconds constituting-a base time interval.

When the pick-up relay RIIiIl operates, it prepares, at the contacts IBI, the previously mentioned circuit for operating the meter relay RI 40; which circuit includes the wiper of the timing switch 90 and the engaged home contact in the associated contact bank, as well as the vertical wiper I4 of the Strowger mechanism 10. Accordingly, the meter relay RIM is operated shortly following operation of the pick-up relay RIBO, while the wiper 95 of the timing switch 90 occupies its home position, provided the vertical wiper I4 of the Strowger mechanism 19 has engaged a contact in the associated contact bank terminating one of the zone conductors CSI, C62, or C63, since the cams CZSI, C262 and CZ63 operate shortly following operation of the pick-up relay RI60 to apply ground potential to the respective zone conductors CBI, C62 and C63. In the present example the vertical wiper 14 of the Strowger mechanism I0 does not engage one of the contacts in the associated vertical contact bank terminating the three zone conductors CBI, C62 and C63 since the present call is a local call; accordingly, ground potential is not applied periodically to the vertical Wiper I4 of the Strowger mechanism 10 and the meter relay RIM! is not operated periodically. In fact, the present local call is not timed; the meter relay RIM! is not operated; and accordingly the magnet MB associated with the meter in the line circuit I] individual to the party subscriber substation B is not operated.

The present local call is maintained during the convenience of the subscribers at the calling party subscriber substation B and at the called private subscriber substation C; and at the conclusion thereof, when the subscriber at the called private subscriber substation C disconnects the connector I92 operates in order again to reverse the polarity of the loop circuit extending back to the calling party subscriber substation B; whereby the answer relay RIIII in the selector 2'! is poled to restore. Upon restoring the answer relay RI'Ill interrupts, at the contacts I'II, the multiple point in the circuit for operating the motor MSI of the impulser 60; whereby operation of the impulser lill isarrested at this mechanisni'fli. When-ground potential is thus removed from the control wiper T3- cflthe Strowger mechanism 10-, the holdi'ng'circuit for'energizing the upper winding of the' pick-no relay R1611, the multiple holding circuitfor energizing the Windingof the switching relay EH39 and the holding circuit for energizing the winding of the cut-01f relay Bil-9 are interrupted causing the relays mentioned to restore." Also" the removal of groundpotentia-I from the control wiper 8 of the finder'26 brings about the releasethereof.

Further, when the switching relay R I 39- restores, a circuit is completed for operating therelease magnet, not shown, of the' Strowger mechanism '70; whereby the Strowger mechanism- 1-9 is released and returned to" its normal" rotary and vertical positions. Also upon restoring the switching relay RI3 B completes, at the contacts 138, a circuit, including-"the contacts "92} thewiper 93 ofthetiniihgswitch 99 and the engaged contact in-the associatedcontact bank include imtheegrounded' multiplef'onoperatingtherotary magnet M91. H Upon=- operating therotary magnet M9I interrupts,a-t'the-contacts 92, the operating circuit therefor; whereby" it. restores to 'drivethe wipers notedPoi' the timing" switch 99 an -additional" step in the clockwise direction;

'and to recom-plete; at" the contacts 92", theoperatingcircuit' theref-br'; Accordingly, the rotary magnet MES-I? operates buzzer fashion to drive the wipers noted' of" the timing switch" 90 step; by step-'- in the clockwise direction back intotheir home positions; whereupon the Wipe-r 93 f the timing switch" 90 engages the' home contact in I the associated: contact bank that is" not'ii'rcluded in; the grounded multipiementionedithus arresting further operation. ofthe" rotary magnet M9I At thisttime, the link'j25' is completely" released "and is markedviatthe' conductor C9as idle to the distributor If! 9 so that it-l may" be again? as- :si'gned foru'se thereby. I v ,v Whenthe. cut-oil" relay R'I'O'jin the. line: circuit IT; restores, it interrupts at the contacts t; the na'th'for applying ground potential'to thefcontroli'oonductorr Cfi'iofthe party subscriber line I";

whereby? the party subscriber. line If' is. marked- :as idle to the connectorshaving access" thereto.

O.f course wl'iile the; connector. I792. engages tli e nrivate subscriber l'i'ne'lfijthe private. subscriber line 5941 is. marked! by; the. associated'iin'eucircuit 1I.93as V-b'usy to theoth'ei: connect-brain the associatiedi group. having" access; thereto; j andlwhen the. connector I 9211s., released the privatesub;- clibeii line I.941is mark'edQhj the associated line circuit. IE3 as idle; tothe other connectors in the associate digroupl; having; access. thereto. 1 'Atl this time the? established. connection. between} the calling; party subscriber sqbsmncnn m. the called private subscriberssubstation Ccissreleasecl aHQLElL-Of: the apparatusiinvolved thereinsis coinpletely releasedandavailablefor;further: use.

In View! of; t 1e: fioregoingh it-will be understood theta i local; call may be, extended f tom stheicalle ing f rstparity subscriberi substation. A o'n the party} subscriber line; I to ealled primate; subrs r-zsu s i msachets-r; m e-asthe e r-1+ position at the-co 10 vote subseriberisutstation (Li an identical man'- ner. In this case it is noted that each time the subscriber at "the calling first par ty subscriber substation A dials=a digit of the directory number of-the called private subscriber substation'Cthat the set ot switch springs SII I in" the associated 'dial'is operated and remains operated until the 'fin g er' WhG'GI of 'a1- is" returned to normal lusion of the transmission of the digit'by the dial; wher by groun potential some calling firstparty subscriber sub tation A reapplied to: the ositive lineconductcr $31 of the; arty subscrib'er'line I dui i'ng the'" dfaling'of each dig-it thereat. This afipl-ication of ground potential at; thes'et or switcnsprings S'I'I-I in the dialat tlie calling first natty" subscriber substatron e to the positive line; conductor or r the party subscriber line I' completes a pathginclud ing thelinewipei I of the finder 26" and the c taot's I33, for short-cifcdting in seristli'e; 10W windings ofthe party relay R125 and the-line eiay-R nein the" selector 21'; whereby the'p'aft y relay R1 20 operates3'-it being of the diif'er'ential types incident to: the cuaiir'ig or the firstdigit of the Tdil ectdry number of the called Lil-Nate subscriber substation-C at the calling" H t par ty subscriber" substation A; whereas the-line relay R] are follows-the imeuis'es' or; the first-unmanned in the: manner previously explained; Upon operating theparty relay R completes, at the contacts- I 2]; a: circuit for operating the' transfer rem: R159; "whereby th latte'i rel'ay' compl" atthe contacts I53; a'fi holding circuit for e r gi'zinethe winding thereof in series with the W-inding of the test relay R1 05 via; the contacts Iii-I When this holding circuit coinpletdtlie' transfer relay RI miners-mes nperatednositi'on; however the" test relay Rl os is not opernee Subsequently; wlie'n tne'sewctor 21- elects thetrunk Ierextendine to the idle onneetor: I92 and the connector" I 92 Y is seized returning-ground potential i via the control-r conductor of the trunk I91 tothe: controiiwiper HottheStrowgef mechanism: 10; a: multiple-holding:circuit-is c'omole'ted for energizing the winding of: the-- tran rerreia-y Rt5'0E-:- 'Upon operating the transfer relay R inte uots; at'ther contacts I5I -,va;.furtherpoifit i'meteri'ng ci rciiit, including the booster bat tery'BB20r;: and repares; acme contacts 23 a furtherpoin-t in a metering circuit;- includin the booster battery BAH; however the: booster batte'ry' circuit mentioned: is not completed atthis time sincethe imeterl relay" RI 407 is not operated .1 during the? presentdoca f. call A'cc'drdinelyL the nection:between thecallingi first par-ty subscriber substation; and the called private subscriber substation well asthe: ultimate release thereo f,- arethe same'as spreviously explained. Specifical-1y:,:when the connector I 92: is ultimately released -ground potential is removed from the control conductor: of: thetrunle I9 I and consequently fromthe controlswiner l3aofthe strowgei' Rl in the line circuit I1; all in the manner previously explained.

Considering now the extension of a trunk call from a calling second party subscriber substation,

such-for example, as the second party subscriber substation B in the central exchange I00 to a called private subscriber substation, such for example, as the private subscriber substation D in the distant exchange IOI, the subscriber at the calling second party subscriber substation B first initiates the call, dials the prefix digit 2 designating the distant exchange IOI included in the second zone of the telephone system, and then dials the three digits comprising the directory number of the called private subscriber substation D in the distant exchange IOI. When the call is initiated at the calling party subscriber substation B, the line circuit I'l individual to the party subscriber line I is controlled in order to govern the distributor H0; whereby the link 25 illustrated may be assigned; whereupon the finder 26 operates to find the party subscriber line I; all in the manner previously explained. When the subscriber at the calling party subscriber substation B dials the prefix digit 2, the Strowger mechanism III in the selector 21 is operated in accordance therewith in order to select the group of trunks, including the trunk 80, and to position the'vertical wiper I4 upon the contacts in the associated vertical contact bank terminating the second zone conductor C62 extending to the set of switch springs SZ62 governed by the zone cam CZBZ. At the conclusion of the prefix digit 2, the Strowger mechanism operates to select an idle trunk in the group, including the trunk 80; whereby the switching relay RI30 is operated as previously explained. Assuming that the trunk 80 is the first idle trunk in the group mentioned when the Strowger mechanism 10 operates to seize the trunk 80, the trunk circuit 90' is seized and the switching relay RI 30 is operated in order to switch through the selector 21. The trunk circuit 90' seizes the automatic switching 'appa: ratus I05 in the distant exchange IOI over the trunk line 95' extending between the central exchange I00 and the distant exchange I 0|. At this time a direct loop circuit is completed between the calling party subscriber substation B in the central exchange I00 and the trunk circuit 90' via the party subscriber line I, the finder 26, the

selector 2! and the trunk 80. Accordingly, when the subscriber at the calling party subscriber substation B dials the three digits comprising the directory number of the called private subscriber substation D in the distant exchange I M the trunk circuit 90 responds thereto repeating the three digits mentioned over the trunk line 95' to the automatic switching apparatus I05 in the distant exchange IOI'; whereby the automatic switching apparatus I05 operates to select the private subscriber line I02 extending to the called private subscriber substation D.

The subsequent operation of the automatic switching apparatus I05 depends upon the idle or busy condition of the private subscriber substation D at this time as marked thereto by the line circuit, not shown, associated with the private subscriber line I02; all in accordance with conventional practice. In the event the called private subscriber substation D is busy at this time the automatic switching apparatus I05 operates to return busy tone current over the trunk line 95'; whereby the trunk circuit 90 repeats the busy tone current over the connection to the calling party. subscriber substation B indicating to the subscriber thereat that the desired connection may not be had immediately by virtue of the busy condition of the called private subscriber substation D in the distant exchange IOI at this time. On the other hand, in'the event the called private subscriber substation D is idle at this time, the automatic switching apparatus I05 operates to project ringing current over the private subscriber line I02 extending thereto and to return ring-back tone current over the trunk line 95; which ring-back tone current is repeated by the trunk circuit 900 over the connection to the call ing party subscriber substation B.

Assuming that the called private subscriber substation D is idle at this time, when the subscriber thereat answers the call, the automatic switching apparatus I05 is controlled in order to govern over the trunk line 95 the trunk circuit 90'; whereby the polarity of the loop circuit extending betwen the trunk circuit 90' and the calling party subscriber substation B is reversed effecting the operation of the answer relay RI'I0 in the selector 21. Upon operating the answer relay RI'I0 initiates operation of the impulser 50 in the event the impulser is not operating at this time. Subsequently, the cam CSI efiects operation of the pick-up relay RI5 0; whereby the latter relay prepares, at the contacts I6 I the circuit for operating the meter relay RI40; which circuit includes the wiper 05 of the timing switch and the engaged home contacts in the associated contact bank, as well as the vertical wiper I4 of the Strowger mechanism 10 and the engaged second contact in the associated contact bank. Subsequently, the second zone cam C262 closes and then opens the associated set of switch springs SZBZ applying ground potential to and then removing ground potential from the second zone conductor C62; whereby a circuit substantially identical to that previously traced is completed and then interrupted for operating the meter relay RI40; whereby the latter relay operates and restores. In fact, the second zone cam CZBZ comprises two projections; whereby the associated set of switch springs SZ62 are closed and then opened twice in succession in order to effect operation and then restoration of the meter relay RI40 twice in succession as explained above. Upon operating the meterrelay RIM) interrupts, at the contacts I42, the normal connection, including the contacts I36 between the control wiper 13 of the Strowger mechanism I0 and the control wiper 8 of the finder 26; and recompletes, at the contacts I4I, a connection, including the contacts I5I and I36 between the booster battery BB20 and the control wiper 8 of the finder 20. Subsequently, when the meter relay RI40 restores, it interrupts, at the contacts MI, the path for connecting the booster battery B1320 to the control wiper 8 of the finder 26; and recompletes, at the contacts I42, the normal connection, in cluding the contacts I36, between the control wiper 8 of the finder 26 and the control wiper I3 of the Strowger mechanism 10. When the booster battery BBZD is connected via the above traced path to the control'wiper 8 of the finder 2E; current therefrom energizes the winding of the switching relay in the finder 2B retaining the finder 26 in its operated position, current therefrom energizes the winding of the cut-off relay R|0 in the line circuit I retaining th cut-01f relay RID in its operated position and potential therefrom is extended via the conductor C4 of the party subscriber line I and the-contacts I3 to the magnets MA and MB of the two meters in the line circuit I 'I-respectively associated with T3 the; party subscriber: substations-21m and-1i Bat: Also each time: the second: zone cam: C2626: operates tmciose' the associated switch springs S262, the thirdizoneqcam 626-3 5 operates-toclose thee asses cia'ted set of switch-springs SZBiv. Each tiihe the third z-one' cam CZG-S closes anditheniopensthe associated set; of switch springs- 82631 'a d'ine'ct circuit-is: completed and" their interrupted for operating-mismatching relay-R I 8 II a-nd a: multi pie path: i's completed and then: interrupted for applyingground potential to 'therthird zone condilator: C5 3 Acc'ordin'glyi the matchihgz' relay R- I 80"is--'0perated eacii timeithe meten relay! R1 40 istoper ated; whereby the" matching relay: R180 c'ompietesg-at tiiecont'acts I 81 a path for connectingthe exchange battery EB48 to" the mag:- netsalVIB and-" Mw of the two meters in the linecii'cuit I' I respectivelyassociated with the party 'subsoritier substations: and lhth e present example; "the booster battery" BB2 Ir iseconnected Y 'ti'irou-gki the=cii cuit traced above'totiieexchange I tattemmatasa whereiiy the two ma'gnets 'MNanq are 'energized iir series circuit: relation: from tliei Booster battery BB'ztiand the exchange-bat- 't'ery'EBM? 1 Since-the magnet r of-"t'he meter 'iil th linE circuit 1 1 individual 'to the zpartysub- -'s1= 'r be 1 sufi'station A isof the marginal type;- it

ates not? operate; however; tliema'gnet of tfi'bi meter the line circuit IT individual to the parts subscriber suhst'ation -B doesep'erat'e. I Ac cording ly,- at t1iis'-*"time"the: meterlVLK in" the" line circuit I 'l iinditiduaily associated with the party subscribersubstation -Nis not operated; whereas B operated? Specifically; the second zone cam I GZBZ' effectS two successive applications of ground V poteiitial i'f()--tliesecond zone conductor C62;

while" the wiper 95 of the timing sWitch-90 'oc5 fi llfl isoperateii and' restorei 't'tvice suc' ces'sion" tobringafiout two "successive-operations 0 he magnet'MBfof-the meter iiithe liiie ci'rcuitx [I -1- ingiividualto thepart'y subscriberiinwBi Also 'each time"-the meterrelay"Rl fifl -operates; iiiin g terrupts, at the contacts I42, the connection-to tiicontmiwiper"1-3 of "the StroWgermechani-sm 'fil fas breikiously' noted jgthereby to-prevent cur: rent from thebooster battery BB2!) from feeding via; the. control wiper 13 0f: the= Str'owger mechj anism Hr-and. the control' conduetor--C83= -of"the t'ttittie control conductor C83 oft-he trunk 650 ftfieretiy-to' preventexcessive and uselesswur rentl 'fiombeing" supplied from the booster battery 3. m 7 After the magnet: MB? has'beenoperatedtwice in succession underth'e controlof 'tifeineter rel' ixy' "assoeiated%'witii=-' the par ty subscriber substation third zcneecam 6253 to: effect-operationnflthe; matchin; relay R-Mm; whereby theimeter: relay R I I I! is again op-erat-ed andkrestored: twice" in suc cession to bring about two additional operations ofth'e magnetMB associated -with the meten in' the l-ii iecircuit- I'I 'indjivi'dual' to the partj sni scrik ier'substatibn lif In viewoff'the foregoingz; itwili h e-understood whenthe-*- present trunk extend'w f-i om' the calling iparty sukiseriber substation- B in' tfiWGBI-i? m1 exchange I IIE to tiie called-private subscriber substation D in the distant exchange I-B'F and subsequently answered by the subsorib'ev'at the called private subscriber" substation D; that-the answer relay R1 19 in the selector 2--1-'i's operated in order'to'eause operation 'sh'ortlythereafter of the m etei" may RE! 4& inthe' seiector '2"! twice in succession under-the contro1= "ofthe' impulser fill'i the meter rei'ayR i dn' the -selector 21 Seineop elated twice in-fsucc ession' by virtue ofitiiefict that th-e 'prese'nt trunk call "extended "to the-dis? taut exchang IfiI resides in the seconckzorie'of the tel-ephone system" with respect" to the central exchange I III); wherebvth'e"meterMBffin' th'e 'li-ne circuit I i individually, associated with the ing, part'y' subscribefsubstation operated twice" in succession-t m order to" register'two "call" unit's: Thereaftershoulditheestabiished corinec'e tion he maintaine'd foraniadditiona'ltime"inter; val of 100" seconds," the? impulser 60. again" 'op;er:.=- a'tes twice in successionjthe m'et-e11"'re1ayj RHOIii the selector 21?? as previously explained"; whereby th'ezmcter MB in the. line circuit" I1'indiizidi1a11$z associated 'with.the party subscriber; substation B" is again operated' 'twi'ce in. succession. in orderto V registerjtwo additional. call unit's. Oifcourse, in the event the;establishedjjconnectiont.prevails" for an extend-ed, time interval the impmser 611 continues to:governiheimeter' relay; RJI 40. inatfie selector 2?! fatthe expiration. of each" lo'oi second'sz whereby; the meterin theline. circuitJIiIid'i; vidu'ally associatedlwith the (party: subscribenisubstation .Biisnpereiaedntwo .additionai timesttonreg s ister. two. additionallcalliunit's; at the; expiration ofleachradditionaL-lm) secondsathe trunkrcireuitriw iseinterrupte I tmnis cirouitdsmi isrreleasedhefieetingethe.

At thezkconclusioniofiithe*establishedflconnection when the subscriber atvt'lie cailedfiprivatesues scriher. substationsllin ether .distantiexchangesI-UI disconnects the; automatic switching apparatus 'I05"governs.over thetnmkJineJS' mmmm; circuitififl; whereby. the polarity;oflthehloomcire cuitf-extending,betweenithescallingh party; subs s'ci'iber substation. BY andthe tmnie,circuitifii: is reversedlin order toipolep-the answer relay} RIM izoqcestoma; ilponw'restoringi-theanswer abiawRIJ-fl interrupts-,1 at: thescontacts. I I I themultiple cine cu-it tfcnioperatingmthesmotonMfiIw otthe impulsesend-enE-IL Subsequently, whenstheesubscribergat the calling partwsubscriber; substation; J3; diSGQI-ii nests, thee loopgcircuithextendin therefiiqomito .wherebygthe eases" over the trunk line 95' of the automatic switching apparatus I05 and interrupting the return of ground potential over the control conductor C83 .of'the trunk 80. The automatic switching apparatus I05 is then released; whereby the subscriber line I02 extending to the private subscribersubstation D is marked as idle thereto. When ground potential is removed from the control conductor C83 of the trunk 80 and consequently from the control wiper I3 of the Strowger mechanism III, the selector 2! and the finder 26 are released in the manner previousl explained. Also the cut-oil relay RIO in the line circuit I'I associated with the party subscriber line I is restored marking the party subscriber line I as idle to the connector having access thereto.

In view of the foregoing description of the extension of a connection from the calling party subscriber substation B in the central exchange I to the called private subscriber substation D in the distant exchange IOI residing in the secand zone of the telephone system, it will be understood that trunk calls from the calling party subscriber substation B in the central exchange I00 to subscriber substations in exchanges residing in the first and third zones of the telephone system may be completed in an identical manner. Of course, trunk calls are routed to exchanges respectively disposed in the first and third zones of the telephone system in response to the prefix digits 3 and 1; whereby the vertical wiper I4 of the Strowger mechanism I0 engages the respective third and first'contacts in the associated vertical contact bank respectively terminating the first and third zone conductors CSI and C63 extending to the impulser 60. Accordingly, when a trunk call is completed to a distant exchange disposed in the first zone of the telephone system, the vertical wiper I4 of the Strowger mechanism engages the third contact in the associated vertical contact bank terminating the first zone conductor CSI; whereby the first zone cam CZfiI of the impulser 60 transmits one ground impulse each ten seconds thereover bringing about one initial operation of the meter relay RI40 in the selector 2! and an additional operation thereof every 100 seconds or base time interval; all inthe manner previously explained. Similarly, when a trunk call is completed to a distant exchange disposedin the third zone of the telephone system, the vertical wiper I4 of the Strowger mechanism I0 engages the'first contact in the associated vertical contact bank terminating the third zone conductor C63; whereby the third zone cam CZ63 of the impulser 60transmits three ground impulses each ten seconds thereover bringing about three initial operations of the meter relay RI40 in the selector 21 and an additional three operations thereof every 100 seconds or base time interval; all in the manner previously explained. I v

In view of the foregoing it will beunderstood that the extension of a trunk call from a calling first party subscriber substation, such for example, as the first'party subscriber substation A in the central exchange I00 to a called private subscriber substation, such for example, as the private subscriber substation D in the distant exlink 25 illustrated, the trunk circuit 90' and the automatic switching apparatus I may be utilized to complete the established connection; all in the manner previously explained. In this case the party relay RIZD in the selector 21 is operated as a consequence of the closing of the set of switch springs SI II incorporated in the dial at the calling first party subscriber substation A incident to dialing the prefix digit 2; whereby the transfer relay RI50 is operated and retained in its operated position. The operated transfer relay RI50 substitutes, at the contacts I5I and I52, the booster battery BA40 for the booster battery B1320 as previously explained. Accordingly, when the call is subsequently answered at the called private subscriber substation D in the distant exchange IOI, the answer relay RI'I0 in the selector 21 operates in order to initiate operation of the impulser 60 in the event it is not operating at this time. The impulser 00 effects operation of the pick-up relay RI 60 and the subsequent operation of the meter relay RI40 twice in succession, as well as operation of the timing switch all in the manner previously explained. In the present example, each time the meter relay RI40 operates, it completes, at the contacts ill, a path, including the contacts I52 and I36, for connecting the booster battery BA40 to the control wiper 8 of the finder 26. Accordingly, each time the meter relay RI40 operates and then restores, both of the magnets MA and MB respectivel associated with the two meters in the line circuit I! respectively associated with the two party subscriber substations A and B are operated. Thus, in the present example, both of the meters mentioned are operated twice in succession initially and are operated twice in succession at the expiration of eachseconds or base time interval thereafter. This result is brought about by virtue of the fact that the booster battery BA40 has a normal voltage of 40 volts, whereas the booster battery BB20 has a normal voltage of 20 volts so that each time the 40 volts booster battery potential is connected to the control wiper 8 of the finder 25, both of the magnets MA and MB operate, the magnet MA being of the marginal type as previously explained.

The subsequent release of this established connection between the calling party subscriber substation A in the central exchange I00 and the called private subscriber substation D in the distant exchange IN is the same as that previously described. :Also it will be understood that the metering from the calling first party subscriber substation A to called private subscriber substations in two exchanges respectively disposed in the first and third zones of the telephone system are the same as previously explained.

Reconsidering the over-all operation of the meter magnets MA and MB of the respective meters respectively associated with the party subscriber substations A and B on the party subscriber line I, it will be observed that while the impulser or impulse generator 60' is operating the matching relay RI80 is operated intermittently. In fact, the matching relay RI 80 is operated three times successively by the set of switch springs SZB3 under the control of the third zone cam CZ63 upon each revolution of the operating shaft of the impulserv 60 driven by the motor MSI. Since the operating shaft mentioned is rotated by the motor MBI one revolution every ten seconds, the matching relay RI80 is operated thirty times each 100 seconds or base time interval. Each time the matching relay RI 80 operates, it completes, at the contacts I8I, a path for connecting the negative terminal of the exchange stances battery EBlBto the'lower terminal or the magnet,

MB, as'well asmultiple" paths for cohnecting the negative terminal of the exchange battery E1348 to the"corresponding terniinals' of the other meters both in a the party. subscriber line circuits and" in the private subscriber line circuits the associated group. However; the connec'tioniof the negative termina'l of the exchangebattery EB48 to the lower" terminalof the magnet MB is Without effect unless of coursei the party sub scrib'er line- I is connected" to a link; such for ex'ai'nple, as the link 25 illustrated. In the last mentioned case,- the cut-off relay R I the hire circuit 1''! ihdividualto'the party subscriber line I occupies its o'peratect position completing, at the contacts l3; the previously traced" patlr" for connecting" the upper terminah of, the mag-netzMh to the control conductor 0 1 of the party sub-=- scr-"iber line I and consequently to the control wiper: 8 of the finder 28;. Which control wiper 8 of the finder 26" has ground or positive" exchange battery potential normally connected theretoras previously explained.- Accordingly;. in the event thefparty subscriber line I is'co'nnected' to thelink 25; the magnets MA and MB'are' energized= in series circuit relation from the exchange battery E348 each timethe matching relay RI'BG o'p'er ates; However, neither or the" magnets" MA or MB is operated by virtue .of vthe low voltage}.- 48 volts; of the exchange battery'EB48 and the high series resistance of the windings of the magnets MA and MB. v Subsequently; however, when the meter relay RMOdn the selector 2'! is operated;- the positive tcrm-inalo'f either the booster battery BA'Ml or the positive terminal of the boosterbattery BBZO is connected-Vito the controlconductor of the link 25'asground potential is removedtherefrom; depending upon whether the party subscriber substation A or B is respectively the calling party subscribersubstation involved in the established connection; all as'previously explained. When the positive terminal of the booster battery BBZO is thusconnected to the control wiper 8 of the finder 26 and consequently to the upper terminal of the magnet MA" and'matched againstnthe negative terminal of the exchange battery EB48, a total voltage of- 68' volts is impressed across the series connected magnets MA' and MB; whereby the magnetMB operates but the -magnet MA does not operate. On theotherhand; when thepositive-terminal-of the booster battery- BAM) is-con nectedto the upper terminal ofthe magnet MA and matched against the negative terminal of the exchange battery E1348, a-totalvoltage of 88 volts is impressed across the series connected magnets and MB, cau'sing both of them to operate. This matching-arrangement-is very advantageous as it prevents undue current drainsirom the exchange battery EB48' during the time. interval that the party subscriber line I isbu'sy b'utiis not beingmetered by the associated link" 25'.- Also the arrangement wherein the matching described above is brought about directly in" the coils of emag'riets of the twometers greatlimihirriizes tharetiuired apparatus enmmating control relays. Iii View of the" foregoing it will be understood that theextehsioh of local and trtnrca'usrrbma calli'rigprivate subscriber" substation on a' private subscriber line in the" group; including the party subscribefline l, via'the' link 25" illustrated are tliesa'meas described inconjunction vviththe second party subscribersubstation B on the party subscriberljne i. This result folloivs sinc'e'the private, sulcis'c'riber substation mentioned eem: firises', like tlie second party subs-enter substation 13; a conventional dial so that the party relay RIM and the transfer relay R150 in the selector 2 of the link 25 are not operated incident to the extension of the local or trunl; calls therefrom. Of course, in this example, the line circuit associated with the private subscriber line mentioned comprises onlyone meter having a magnet wh ch is operative when the exchange battery EB -w is connected under the control or the matchlng relay Riiiu to one terminal thereof and when the booster battery BBzZo is connected under the control1 or; the meter relay Rum to the other terminal thereof. Accordingly, the meter in the line circuit associated with each private subscriber 15 line reads directly the service rendered to the connected private subscriber substation. V

View of the foregoing explanation of the modem operation or the telephone system, it will be understood that Zone metering is carried out on a unit call basis depending: upon the zone of the distant exchange or the called subscriber substation With respect to the central exchange lot) and 01' course upon the time duration or the established connect ons since the meters are operated initially a short time aiter a trunk connect on is established and thereafter at the expiration of each additional loo seconds or base tlme interval Also it Will be observed thatthe reading or the. meter individually associated with a first party Subscribersubstation'or a party sub: scriber line may be taken directly as a measure or; service rendered thereto;- however, the meter reading of; the meter individually associatd with the second party subscriber substation on a party subscriber line must be corrected in order to ob-' tain a measure ofthe service rendered thereto by' subtracting: therefrom the meter reading; of the-meter individually associated with the first party subscriber substation 011112116 party subscriber' line,- ThlS result follows from the circumstance that the meter individually associatedwlth thefsecond party subscriber substation on the party subscriber line is falsely operated each time the meter-V individually associated with the first party subscriber substation on" the" party" subscriber line is properly operated: While this scheme necessitatesa minor calculation in'order to 'obtain a measure of the service rendered to each sebond party subscriber substation on a party s'ubscriber-line,-the circuit arrangement is greatly simplified permitting the utilization of a conventionarfinder of the Strowg'er ty e in each finderselector lihliand eliminating the usual meter-- Slfihg SWilJoHllOihlaHy disposed in the lll'l' Oilc'll-lt a s'sooiatd 'vvith each party Subscriber liill 11 i View of theforegoingit is apparefitthat therehas: can provided atelephone system coriiprising party mies or the tWo' part subscriber substatiom type and? improved zone metering facility whereby the services rendered to' the respective party"subscriber"substationson a party subscriber line 'rnay be respectively meteredoii unit can basis depehding upon the z nesor thecan'eaexchangeswith reference to" the zone df the calling exchange; asu'ifell a's thetin'ie' duration of theestabli'shed connections:

Whi e there has been described" that is at present considered to be the" p'rererreti'" embodi 4' ion, it Will'beuiiders't (id that s modifications"bniadftlierein'; and itjis menseswecaves-muleappended claims an such modifications as fall" Within the trile' "spirit 'afi'id'fsjc'opeofth'e fition. v Wha is'claiihe s. v H c 1: Ina"telephonesystehiihbludin g a part iiiie having first and secondstations thereon, a first meter individual to said first station, asecond meter common to said first and second stations, automatic switching apparatus, and means controlled from either calling one of said "stations on said party line for operating said switching apparatus to extend a connection therefrom; a first source of potential, a second source ofpotential, means included in said switching ap paratus for identifying the calling one of said stations, means governed by said identifying means for selecting said first source of potential incident to the identification of said first station as the calling station and for selecting said second source of potential incident to the identification or" said second station as the calling station, andmeans including said selected first source of potential for operating both said first and-second meters and including said selected second source of potential for operating only'said second meter so that said first meter is operated to measure service rendered only to said first station and said second meter is operated to measure service rendered to both said first and second stations. Y

2. In a telephone system including a party line having first and second stations thereon, a first meter individual to said first station, a second meter common to said first and second stations, automatic switching apparatus, and means controlled from either calling one of said stations on said party line for operating said switching apparatus to extend a call therefrom; a first source of potential, a second source of potential, means included in said switching apparatus for identifying the calling one of said stations, means governed by said identifying means for selecting said first source of potential incident to the identification of said first station as the calling station and for selecting said second source of potential incident to the identification of said second station as the calling station, and means responsive to answering of said call for operating both said first and second meters if said first source of potential is selected and for operating only said second meter if said second source of potential is selected so that said first meter is operated to measure service rendered only to said first station and said second meter is operated to measure service rendered both to said first and second stations.

3. In a telephone system including a party line having first and second stations thereon, a first meter individual to said first station, a second meter common to said first and second stations, automatic switching apparatus, and means controlled from either calling one of said stations on said party line for operating said switching apparatus to extend a call therefrom; a first source of potential, a second source of potential, means included in said switching apparatus for identifying the calling one of said stations, means governed by said identifying means for selecting said first source of potential incident to the identification of said first station as the calling station and for selecting said second source of potential incident to the identification of said second station as the calling station, and means selectively controlled in accordance with the extent of said connection for selectively operating a corresponding number of times said first and second meters in series with said selected first source of po tential and for selectively operating a corresponding number of times said second meter in series with said selected second source of potential so that said first meter is operated to measure serv ice rendered only to said first station and said second meter is operated to measure service rendered both to said first and second stations.

4. In a telephone system including a party line having first and second stations thereon, a first meter individual to said first station, a second meter common to said first and second stations, automatic switching apparatus, and means controlled from either calling one of said stations on said party line for operating said switching apparatus to extend a call therefrom; a first source of potential, a second source of potential, means included in said switching apparatus for identifying the calling one of said stations, means governed by said identifying means for selecting said first source of potential incident to the identification of said first station as the calling station and for selecting said second source of potential incident to the identification of said second station as the calling station, means responsive to the answering of said call for operating both said first and second meters in series with said selected first source of potential and for operating only said second meter in series with said selected second source of potential, and timing means controlled a fixed time interval after answering of saidcall for reoperating said first and second meters or only said second meter in accordance respectively with the selected first source of potential or the selected second source of potential so that said first meter is operated to measure service rendered only to said first station and second meter is operated to measure service rendered both to said first and second stations.

5. In a telephone system including a party line having first and second stations thereon, a first meter individual to said first station, a second meter common to said first and second stations, automatic switching apparatus, and means controlled from either calling one of said stations on said party line for operating said switching apparatus to extend a call therefrom; a first source of potential, a second source of potential, means included in said switching apparatus for identifying the calling one of said stations, means governed by said identifying means for selecting said first source of potential incident to the identification of said first station as a calling station and for selecting said second source of potential incidental to the identification of said second station as the calling station, mean selectively controlled in accordance with the extent of said call for selecting a corresponding number of times that the first and second meters or only said second meter is to be operated answering means operated responsive to answering of said call, means controlled by operation of said answering means for operating said first and second meters in series with said selected first source of potential said selected number of times or for operating only said second meter in series with said selected second source of potential said selected number of times, and timing means controlled a fixed time interval after operation of said answering means for reoperating said first and second meters or only said second meter said selected number of times in series respectively with said selected first source of potential or said selected second source of potential so that said meter is operated to measure service rendered only to said first station and said second meter is operated to measure service rendered both to said first and second stations.

6. In a telephone system including a party line can automatic switching apparatus, "and means 'controllable from either calling one of said stations on said party line for operatingfsaidlswitching apparatus to extend a connection therefrom; said switchingapparatus including a high voltage source of booster battery and a low voltage source of booster battery, means includedinjsaid switching apparatu for identifying the one of said stations from which said connections is extended, means governedby said identifying means and controlled in the event said first station is identified asthe calling station for selecting said high voltage source of booster battery and controlled in the event'said secondjstation is identified as the calling station forsel'e'cting said low voltage source of booster battery, andmeans including said selected source of booster battery for selectively operating said first and second meters.

7. In a telephone system including a party line having first and'second stations thereon, a first meter individual to said first station, a second meter common to said first and second stations, automatic switching apparatus, and means controllable from either calling one of said stations on said party line for operating said switching apparatus to extend a connection therefrom; said switching apparatus including a high voltage source of booster battery and a low voltage source of booster battery, means included in said switch- I ing apparatusfor identifying the one of said stations from which connection is extended, means governed by said identifying means and controlled in the event said first station'is identified I as the calling station for selecting said high voltage source of booster battery and controlled in the event said second station is identified as the calling station for selecting said low voltage source of booster battery, said first meter'being of the marginal type, and means for connecting said selected one of said sources of booster hat- I tery to said meters so that both said first and second metersare operated when said high voltage source of booster battery is connected thereto and only said second meter is operated when said low voltage source of booster battery is connected thereto so that said'first meter is operated tomeasure service rendered only to said first station and said second meter is operated to measure service rendered both to said first and second stations.

8. In a telephone system including a party line having first and second stations thereon, a first meter individual to said first station, a second 7 meter common to said first and second stations,

automatic switching apparatus, and means controllable from either calling one of said stations on said party line for operating said switching apparatus to extend a connection therefrom; said source and controlled in the event second station is identified as thecaIling station for selectselected'lew voltagesource*"tosaid series circuit so that both said first and'second' meters are operated when said high voltage source is connected to said series circuit and only'said second meter is operated when said low voltage source isconnected to said series circuit so that 'saidfirst meter is operated to'measureservice rendered only 'to'said' firststation and said second meter is operated to measure service rendered both to said firstjand second stations.

9In a telephone systemincluding a party line having first and second stations thereon, a line circuit associated with said party line and provided with a cut-off relay and a first meter-individual to said first station and a second meter common to said firstfand second stations, an automatic switching link, and means controllable from either calling one of said stations on said party line for connecting said line circuit to said link and then for operating" said li'nk'to extend a connection therefrom; a control conductor included in said connection between said line circuit and said link, means responsive to the conofi relay operated over said control conductor, a

first source of potential, a second source of potential, means included in said link for identifying the calling one of said stations from which said connection is extended, means governed by said identifying means for selecting said first source of potential incident to the identification of said first station as the calling station and for selecting said second source of potential incident to the identification of said second station as the calling station, answering means operated responsive to the answering of said connection, means controlled by operation of said answering means for operating both said first and second meters in series with said control conductor and said selected first source of potential or for operating only said second meter in series with said first meter and said control conductor and said selected second source of potential so that said first meter is operated to measure service rendered only to said first station and second meter is operated to measure service rendered both to'said first and second stations.

10. "In a telephone system including a party line having first and second stations thereon, a line circuitassociated with Said party line and provided with a cut-off relay and a first meter individual to said first station and a second meter common to said first and second stations, an automatic switching link provided with a switching relay, and means controllable from either calling one oi'said'stations on said partyline for connecting said line circuit to-said link and then for operating said link to extend a connection therefrom; said connection between said line circuit and said link including a control conductor, means responsive to the connection of said line circuit to said link for operating said cut-off relay and for retaining'said cut-01f relay operated over' said controlconductor, means responsive to the operation of said link to extend saidconnection for operating said switching relay and for retaining said switching relay Operated over said control conductor, a high voltage source, a low voltage source, means included in said link for interrupting said control conductor between said cut-off relay and said switching relay and for ingsaidlow voltage source, {and means 'forl c'onnecting said selected high voltage sourceor' "said selectively connecting said high voltage source andsaid lowvoltage'source to the section of said control conductor extending tosaid cut-01f relay,

1 and means selectively 'tion of said high voltage source and said low controlled by the connecsource to said last-mentioned section of said control conductor for selectively operating said meters.

11. In a telephone system including a subscriber line, an automatic switching link, and means controllable over said line for seizing said link and for operating it to extend a call therefrom; first and second conductors, an impulse generator, means controlled by said impulse generator for intermittently transmitting impulses over said first conductor, means included in said link and governed in accordance with the extent of said call for selecting a corresponding number of impulses to be transmitted over said second conductor, answering means included in said link operated responsive to answering of said call,

' mean controlled by operation of said answering means for transmitting said selected number of impulses over said second conductor, timing means included in said link and governed a predetermined time interval after operation of said answering means for transmitting said selected number of impulses over said second conductor, and a meter individual to said line connected in series with said first and second conductors and operated only incident to the simultaneous transmission of impulses over said first and second conductors.

12. In a telephone system including a subscriber line, an automatic switching link, and means controllable over said line for seizing said link and operating it to extend a connection therefrom; first and second conductors, an impulse generator operative to transmit periodic impulses, first relay means operated responsive to each impulse transmitted by said impulse generator, means controlled by operation of said first relay means for transmitting an impulse over said first conductor, said link including a timer having a fixed number of positions, mean operated responsive to impulses transmitted by said impulse generator, means controlled by operation of said last-mentioned means for advancing said timer cyclically through a given one of its positions, second relay means included in said link and operated responsive to operation of said timer through its given one position, means controlled by operation of said second relay means for transmitting an impulse over said second conduotor, and a meter individual to said line connected in series with said first and second conductors and operated only incident to the simultaneous transmission of impulses over said first and second conductors.

13. In a telephone system including a subscriber line, a meter individual to said line, an automatic switching, link, and means controllable over said line for seizing said link and for operating it to extend a connection therefrom; first and second control conductors, first and second metering conductors, means included in said link and controlled in accordance with the extent of said connection extended thereby for selecting a corresponding one of said metering conductors, an impulse generator operative to apply N impulses per base time interval to said first metering conductor and to apply AN impulses per base time interval to said second metering conductor and to said first control conductor, said link including a timer and means controlled by said impulse generator for operating said timer and means controlled by operation of said timer for connecting once during said base time interval said selected one of said metering conductors to said second control conductor in order to cause one or A impulses to be applied to said second control conductor, and matching means responsive to the simultaneous transmission of impulses over said first and second control conductors for operating said meter.

14. In 'a telephone system including a sub scriber line, a, meter individual to said line, an automatic switching link, and means controllable over said line for seizing said link and for operating it to extend a, connection therefrom; an impulse generator, means controlled by said impulse generator for connecting intermittently a first potential to a first terminal of said meter, and means included in said link for selectively connecting a second potential to a second terminal of said meter, said meter being operated only when said first and second potentials are simultaneously respectively connected to the first and second terminals thereof.

15. In a telephone system including a subscriber line, a meter individual to said line, an automatic switching link, and means controllable over said line for seizing said link and for operating it to extend a connection therefrom; said link including a control conductor, means operated responsive to seizure of said link, means controlled incident to the operation of said seizure means for connecting a first terminal of said meter to said control conductor, means operated responsive to operation of said link to extend said connection, means controlled by operation of said last-mentioned means for connecting a reference potential to said control conductor in order to retain operated said link, an impulse generator, means controlled by said impulse generator for connecting intermittently a negative potential to the second terminal or said meter so that said meter is intermittently energized but not operated, and means included in said link for Selectively disconnecting said reference potential from said control conductor and for connecting a positive potential thereto, said meter being'operated only when said positive and negative potentials are simultaneously respectively connected to the first and second terminals thereof.

16. In a telephone system including a plurality of subscriber lines, a plurality of meters individual to said lines, a plurality of automatic switching links, and means controllable over said lines for seizing said links and for operating them to extend connections therefrom; an impulse generator, means controlled by said impulse generator for connecting intermittently a first potential to a first terminal of each of said meters, and means included in each of said links for selectively connecting a second potential to a second terminal of the meter individual to the connected line, each of said meters being operated only when said first and second potentials are simultaneously respectively connected to the first and second terminals thereof. 7

17. In a telephone, system including a party line having first and second stations thereon, a first meter individual to said first station, a second meter common to said first and second stations, an automatic switching link, and means controllable from either calling one of said stations on said party line for seizing said link and for operating it to extend a connection therefrom; a source of first potential, a source of second potential, a source of third potential, first and second conductors, an impulse generator, means controlled by said impulse generator for v.25 intermittently transmitting impulses from said source of first potentia'fover said first conductor, means included imam link for identifying the calling one of said 'jstations on said line and for selecting said source of second potential in the event said first station; is identified and for selecting said source'of third potential in the event said second station is identified, means included in said link for selectively transmitting impulses from said selected source of potential over said second conductor, and matching means selectively responsive to the simultaneous transmission of an impulse from said source of first poten-' tial over said first conductor and of an impulse from said source of second potential over said second conductor and to the simultaneous transmission of an impulse from said source of first potential over said'first conductor and of an impulse from said ource of third potential over said second conductor'ffor selectively operating said 20 first and second metersf CLARENCE E. LOMAX.

26 REFERENCES CITED UNITED STATES PATENTS Number Name Date 1,799,223 Fowler Apr. 7, 1931 1,858,863 Ostline May 17, 1932 2,089,438 Scudder Aug. 10, 1937 2,225,386 Hebel Dec. 17, 1940 2,250,735 Topfer July 29, 1941 2,282,975 Lurke et a1. May 12, 1942 2,314,961 Williams Mar. 30, 1943 2,322,330 Vroom June 22, 1943 2,428,376 Matthies Oct. 7, 1947 2,468,429 Dehm et a1. Apr. 26, 1949 

